1. Field of Invention
The invention relates to a patch antenna and, in particular, to a double-band multi-mode array antenna.
2. Related Art
The rapid development in wireless communication technology and semiconductor processes in recent years have brought us wireless communication and satellite communication networks, such as satellite positioning systems, direct broadcasting satellites (DBS), mobile satellites (MSAT), wireless phones, wireless area network systems, wireless subscriber exchange machines, wireless area pagers, etc. The wireless communication system is mainly comprised of a transceiver and an antenna. The antenna is the bridge to transceiving electromagnetic signals in air and an indispensable device in the communication system. Currently, the antenna is preferred to be made using printed circuits. It has the advantages of easy production and low cost.
A communication standard commonly used in wireless communications is IEEE802.11a or IEEE802.11b set by the Institute Electrical and Electronic Engineer (IEEE). The IEEE802.11a standard uses the 5 GHz band, and the IEEE802.11b standard uses the 2.4 GHz band. Therefore, the antenna substrate is designed based upon the used band. When the wireless communication system needs to use two different frequencies simultaneously, antennas for the two bands have to be used. This causes a lot of inconvenience. Nowadays, the trend in antenna designs is the dual-band antenna in order to meet the multi-band requirement. Moreover, most electronic devices are designed to be compact and light. The conventional antenna structures are not suitable for such purposes. Therefore, it is an important to minimize the antenna size while keeping the desired antenna functions.